Which radiographic sign is most indicative of epiglottitis?

• A. Steeple sign
• B. Batwing pattern
• C. Thumbprint sign
• D. Ground-glass opacity

Answer: (C)

Epiglottitis causes swelling of the epiglottis, which shows up prominently on a lateral neck radiograph. The swollen epiglottis forms a thick, rounded silhouette that protrudes into the airway, creating a shape that looks like a thumbprint—the thumbprint sign. This sign directly reflects epiglottic edema and potential airway obstruction, making it the most specific radiographic clue for epiglottitis. Other signs point to different conditions: the steeple sign is subglottic narrowing seen on a frontal view and is associated with croup; the batwing pattern suggests edema around the hila seen in pulmonary edema; and ground-glass opacity is a nonspecific hazy appearance seen in various interstitial or inflammatory lung processes.